In some conventional encryption applications, it is necessary to send data to a hard disk to be encrypted and retrieve data from the hard disk for decryption. One such application is personal video recording (PVR). In such systems, the encryption/decryption functions are implemented by separate devices between the ATA host adapter and the ATA bus connector. ATA stands for AT Attachment, a standardized interface used by storage devices such as hard disk drives, CD drives and DVD drives. ATA compatible drives may also be referred to as integrated drive electronics (IDE) drives. One drawback with conventional separate device implementations is that unencrypted or “clear” data is available at the interface between the ATA host adapter and the external encryption/decryption chip, and can be intercepted and stored in unencrypted form.
The encryption used in conventional systems is not particularly “strong” and could be broken relatively easily. Furthermore, in certain instances where data may be made available to various system components, data integrity may be compromised by other components that may gain access to the encryption/decryption keys. This may be particularly true, for example, in systems that utilize a shared bus having a common bus interface.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.